Help with CH please...

[lka674]

Today's numbers:


FC - 12
CC - .5
TC - 12.5
pH - 7.6
TA - 100
CYA - 60
CH - 550

I had to start a shocking process recently bc we had been out of town and the chlorine went to zero, so it's coming down at a rate of about 1ppm in my OCLT's and the pool water does look clear. Suggestions on what to do about pool maintenance when out of town would be greatly appreciated...should we increase the chlorine by 1ppm for the days that we will be gone so that when we come home it's where it should be??

I don't know what to do about our CH though. We live in a very hard water area in a suburb of Austin, TX where we basically must use a salt water softner for our home...so my thoughts were that draining the pool down to replace it with new water as a solution didn't make sense to me b/c I'd just be replacing hard water with even harder water....so, I did a chemistry test on our outside faucet water where we would be replacing water from. The test came back with CH of 160. Just to compare, I also tested an inside faucet that is run through our water softner and the water did not turn pink, but rather purple and just to see what it would take to turn it to blue ended up at 120.

So.....are my thoughts basically incorrect? Dilution IS the solution??

The calcium scaling on our flagstone beach entry and some of the coping is starting to get really bad, so I want to address it ASAP.

Suggestions on how to clean up this scaling in the grout would be great too. We've tried just about everything and I can't clean it off.

Many thanks!
Laura

 

[BoDarville]

lka674:

Suggestions on what to do about pool maintenance when out of town would be greatly appreciated...

Here's quite a few: Maintaining your Pool While on Vacation

I don't know what to do about our CH though.

Since your fill water has a lower CH (160 ppm) than the CH level of your pool (550 ppm), doing a partial drain & refill (D&R) will lower your CH level. Just be aware that you will need to D&R more water than you may think. Use the Pool Calculator to determine how much water needs to be D&R. In the CH section, input your current CH of 550 and the target CH you would like to achieve. Then, on the right side of the CH section, input the CH of your fill water. The calculator will then tell you how much water needs to be replaced.

If you do not want to do a partial D&R (if water is too expensive, for example) there are ways to manage the CH level. Here are a few options to do this:

• 1. Manage your pH and Alkalinity. Keep pH on the lower side of the target range (ideal target rage is between 7.2 - 7.8; to mitigate high CH, keep it between 7.2 and 7.5). Lower TA to the point where the pH remains relatively stable. This may take some experimenting to find out what TA level works well for your pool. Focus on pH first.

• 2. Add a sequestrant to help prevent high CH levels from causing scaling. This will not remove the calcium; it merely binds to the calcium and keeps it from reacting as it otherwise would.

• 3. Whenever it becomes necessary to shock, do not use Cal-Hypo chlorine - it adds calcium. Use bleach or liquid chlorine instead.

 

[lightingguy]

The calcium scale will clean off with acid. Muriatic acid is strong stuff - so you'll want to use a diluted solution and take precautions - wear gloves, eye wear, etc.

If you are using it on natural stone - test your solution in a non-visible space just to make sure you are not staining something.

As mentioned if you lower your CSI the scale issues at the water line should stop - but that probably wont dissolve any hard scale that is already there any time soon.

A few of us have positioned our downspouts to take advantage of rain water in the winter to lower CH. You can also look at reverse osmosis - but it can be pricey.

 

[lka674]

Re: Help with CH scaling and rust staining

Thanks for the replies....and apologies in advance for the novel below:

Considering that it appears I will need to drain/fill 67% of the water, I believe we are going to consider doing it in the fall (we have pretty strict summer water conservation restrictions in the area in which we live). Until then, I think I like the CSI management option. I figured that I could fairly easily keep the pool between -0.21 and -0.3. Is this CSI level good enough to stop the scaling?

My numbers today:

FC - 10 (loosing 1ppm daily)
CC - .5
TC - 10.5
pH - 7.4ish
TA - 90
CYA - 60 (our pool receives 100% direct sunlight)
CH - 550

Playing with the pool calculator, it seems if I can get the TA down to 70 and hold it there with the pH around 7.2-7.4 I could accomplish the CSI levels discussed above. Probably wouldn't be such a bad idea to drop the TA down that low anyway, considering we have several water features that run daily. Would you agree and do you have any idea how long I would need to hold the pH at 7.2 to drop the TA from 90 to 70? I would prefer to stay around 7.2 because my 2 year old swims with her eyes open under the water and doesn't understand yet that she needs to close them when the pH is too low....Also, should I completely stop using the water features while trying to drop the TA?

On the existing scaling and the use of muriatic acid to clean it up....it is soft stone that the scaling has formed upon (TX flagstone beach entry along the grout lines and on the flagstone coping under the spa's spillway), so I guess I will need to test it somewhere first. When you say use muriatic acid, do you mean scrubbing it with a plastic bristle brush dipped in a diluted solution or literally just pouring it on there? I know this may come of as a silly question, but I'm new to all of this as I just took over the pool care from DH and was clueless about any of it until about a month ago. I want to make sure I do it correctly to both get the scale off AND not screw up my flagstone! LOL I assume the muriatic acid will also eat off the sealant (that clearly is not making it easier to remove as advertised... :grrrr: )as well, yes?

And then finally....just because we are talking about clean up...the DH accidentally got some fertilizer onto the tanning ledge (yeah....I know....NOT good) and of course it formed rust stains. He's been slowly working on it over the last few months by scrubbing it with a rust stain remover stone pool tool of some sort..and it is looking "better", I guess....but is there a better way to eliminate the stain? Will a liquid stain remover be ok and would it work without damage to the plaster?

Again, many thanks!
Laura

 

[Richard320]

First hand experience: keep CSI negative, and you will not see any new scale form, and you will see scale dissolve, although at a glacial pace. Keep TA low and pH low since you can't do much about the CH itself. Although I do drain off a couple inches to water the lawn then refill the pool to keep mine down below 800 or so.

For cleaning above the waterline, I'd try a squirt bottle, maybe an empty one from bathroom cleaner or something (well-rinsed!), let it sit, maybe scrub a little with a brush, then rinse and repeat.

 

[lka674]

Thanks Richard! I could not get into your link however to read about your first hand experience.

 

[Richard320]

Try it now

 

[lka674]

Nice job! How negative is ideal here?

 

[Richard320]

It's about -.2 these days with the warmer water.

 

[lka674]

Thanks!